Traditionally, voice and data communications were performed between stationary locations. A communication generated by a source at one location was transferred across a communication medium to a destination at another location. Possible sources and destinations may range from large broadcasting facilities to small communications devices having the capability of transferring voice and/or data information. The communications medium most prevalently used in the past is transmission cables or channels. More recently, wireless communication media, such as radio or infrared, have been used.
When multiple parties, or devices, communicate with one another in a communications system, the interaction between the parties is usually governed by a protocol. A protocol is the handshaking that occurs between the parties when communicating to initiate contact and route the connection. The protocol must locate the desired second party and signal the request for communication. The protocol must also identify the originator and its location to allow the second party to return communication.
The first step in a communication is the initiating of contact. In the case of a cellular phone system and other similar types of communications systems, communication initiation usually occurs on the same transmission medium used to transfer for communications when the system is in normal operation. In other words, in a cellular phone system, the cellular phone initiates calls on the same transmission medium that is used to route calls to it. Since call initiation is performed on the same transmission medium used for communication, the transmission medium must be optimized for two-way traffic. Because of this, the system cannot use transmission media which are optimal for call initiation if those transmission media would not be optimal in providing two-way communication. For instance, two-way communication systems must establish private channels that isolate users from all other system activity. This communication requirement is an obstacle for call initiation because the portion of the communication system dedicated to initiating contact must have the ability to communicate with multiple devices at once, or be forced to wait for the end of one communication before another can be started. Existing systems handle this obstacle using technology of increased complexity.
It is desirable to provide a system in which call initiation is not performed on the same transmission medium as the regular communication of the system so that both transmission media utilized when providing the system functionality and the transmission medium used for call initiation may both be optimized for their independent requirements.
Some protocols, such as those used in a local area network (LAN) environment, usually require that all clients (i.e., a device coupled to the network) identify themselves for the purposes of receiving calls or data packets that may be sent on the network in the future. Without proper identification, messages directed towards a particular client would never be routed to their destination.
The process of a client identifying itself is often referred to as registration. In all the higher level protocol systems, such as LAN protocols and cellular phone protocols, the client agents are required to register to use the system. For instance, if the user of a cellular phone desires to receive phone calls, the cellular phone must be turned on and it has to register. Registration is performed by transmitting an identification to a master station. The master station then completes the registration process by storing the identification as a future reference for communications on the system. In the case of a cellular system, registration comprises sending messages to the nearest cellular phone extension, commonly referred to as a base station. These messages include the phone number of the cellular phone and an indication that the cellular phone is in the area of the cellular phone extension. In response to the messages, the base station notifies a central switching office. If a party is trying to reach the user of the cellular phone, the central switching office is able to route the call to the user through the base station.
Another communication system that uses a protocol is a paging system. A paging system broadcasts messages which are received by a single target paging receiver that indicates to the user that a call is desired. For instance, a paging system can be used to indicate to the user that a phone communication is requested of the user. The page is often no more than a phone number. The page itself indicates the request. A page message is broadcast over a region, country, or worldwide with reception intended for a single user. Communication will succeed if the target user is anywhere within the service region of the page broadcast. Paging can initiate communication without a requirement that the targeted client register its location with the system. Once the message is received, the user of the paging receiver uses a telephone to call back the telephone number. One problem with the typical paging system is its lack of automation. For instance, when using a paging system, the user must locate a telephone in order to complete the communication. Because of this, the user is not able to provide uninterrupted attention to other matters, thereby resulting in reduced productivity. Therefore, it is desirable to provide a paging-type communication system where the call back function is automated.
Although cellular communication systems and paging communications systems exist, other wireless communications systems are in use today. For instance, radio is widely used for short range and long range communication. Infrared communication is also used widely today. Wireless communications systems are often limited in their range of communications. If a receiving device is out of range, the communication transmitted by the transmitting device will not be received. However, the transmitting device often does not know if the receiving device is in range. Therefore, it is possible that messages will be lost without the transmitting device knowing. Furthermore, the prior art protocols for use with radio and infrared communication usually allow the transmitter of a message to send the message independent of whether the message is being received. Therefore, in this case, a completed communication only occurs if the receiving device is set up and ready to receive the message. Thus, if the receiver is not ready, the transmitted message will not be received, thereby requiring retransmission. It is desirable to provide for wireless communication where the communication does not begin until the receiving device is ready to receive a communication or where the transmitting device knows that the receiving device is in range and able to receive the communication.
The present invention provides a wireless communications system that uses an automated protocol to provide communications for mobile devices. The present invention provides for the automated call initiation, transmission and reception of data communications using a wireless communications system. The present invention also provides for hailing communications devices to establish communications.